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Öğe 3D Model of Hittite Yalburt Monument(Iop Publishing Ltd, 2016) Kalayci, Ibrahim; Ogutcu, Sermet; Karauguz, GungorThe objective of this paper is Yalburt plateau which is located 16km north of Ilgin. Height of this plateau is 1300m. There are hieroglyph stone blocks located in the foot of mountain constitutes a pool. This pool was first discovered in 1970 and archaeological dig has been carried out during 1970, 1972, 1973 and 1975. As a result of these archaeological studies, there is a rectangular pool surrounded by the hieroglyph stone blocks with its three sides was discovered. There were no Hittites' remnants found inside and outside of the pool but plenty of ceramics were found from Rome, Byzantine and early Hellenistic era. The total length of hieroglyph stone blocks of the pool is 12.70 m, their thickness is 1.20 m and the width of the pool is 8.30 m. The condition of 18 hieroglyph stone blocks is quite well except a few of them. One tablet describes the family tree of Tuthaliya IV and also describes the king of Hittite's campaign to Lukka lands which consist of Wiianawanta and Pinali countries.Öğe 3D Modelling of Kizildag Monument(Iop Publishing Ltd, 2016) Karauguz, Gungor; Kalayci, Ibrahim; Ogutcu, SermetThe most important cultural property that the nations possess is their historical accumulation, and bringing these to light, taking measures to preserve them or at least maintain the continuity of transferring them to next generations by means of recent technic and technology, ought to be the business of present generations. Although, nowadays, intensive documentation and archiving studies are done by means of classical techniques, besides studies towards preserving historical objects, modelling one-to-one or scaled modelling were not possible until recently. Computing devices and the on-going reflection of this, which is acknowledged as digital technology, is widely used in many areas and makes it possible to document and archive historical works. Even virtual forms in quantitative environments can be transferred to next generations in a scaled and one-to-one modelled way. Within this scope, every single artefact categorization belonging to any era or civilization present in our country can be considered in separate study areas. Furthermore, any work or likewise can be evaluated in separate categories. Also, it is possible to construct travelable virtual 3D museums that make it possible to visit these artefacts. Under the auspices of these technologies, it is quite possible to construct single virtual indoor museums or also, at the final stage, a 3D travelable open-air museum, a platform or more precisely, to establish a data system that spreads all over the country on a broad spectrum. With a long-termed, significant and extensive study and a substantial organization, such a data system can be established, which also serves as a serious infrastructure for alternative tourism possibilities. Located beside a stepped altar and right above the Kizildag IV inscription, the offering pot is destructed and rolled away a few meters to the south slope of the mould. Every time visiting these artefacts with our undergraduate students, unfortunately, we observe more demolishment. This case study aims to construct the extensive data system mentioned above, and in the context of historical artefacts it aims-which is the lowest stage of such a study gathering information about the Kizildag findings using the previously mentioned technologies. This paper will explain how the geometry and texture of historical objects can be automatically constructed, modelled and visualized from digital image processing software. In this context, the second research has been conducted, aimed to obtain the visuals of the Hittite hieroglyph inscriptions located in Kizildag by using digital photogrammetry technique. After obtaining the visuals, they will be evaluated in a photogrammetric software which endues the finally constructed 3D virtual product with its original texture. In this way, the current destructed artefacts mentioned above can be handed down to the next generations in form of scaled, virtual models. We consider this to be of particular importance.Öğe Accuracy and precision of network-based RTK techniques as a function of baseline distance and occupation time(Springer Heidelberg, 2018) Ogutcu, Sermet; Kalayci, IbrahimTurkey established the TUSAGA-AKTIF CORS Network in May 2009. Network software and central server were updated in 2016. With this update, GLONASS message type was determined for Flachen Korrektur Parameter (FKP), Master Auxiliary Concept (MAC) and Virtual Reference Station (VRS) network-based real time kinematic (NRTK) techniques. A 64 bit central server and the Trimble Pivot Platform network software were also acquired with this update. To the best of our knowledge, there has not been a comprehensive accuracy and precision test of the new system yet. In this paper, we aimed to create empirical accuracy and precision model of FKP, MAC and VRS NRTK techniques of the updated system as a function of baseline distance and occupation time. It is intended that surveyors can perform mission planning according to the requirements of accuracy and precision using these models. Seven test points and two check points were chosen to conduct the experiment. The baseline lengths with respect to the closest continuously operating reference stations (CORS) station were determined as 5-20-40-50 km approximately. Three thousand epochs with 2-s sampling interval were obtained for northing, easting and ellipsoidal height coordinate components of NRTK techniques at each point. Assumed true coordinates of each test point were determined by static survey using the GAMIT/GLOBK scientific software. In terms of accuracy and precision, our results show that empirical accuracy model depends only on the occupation time while empirical precision model depends on both the baseline length with respect to the closest CORS station and the occupation time for each NRTK technique. The results indicate that estimated accuracy and precision models can be safely used for mission planning purposes.Öğe Displacement monitoring performance of relative positioning and Precise Point Positioning (PPP) methods using simulation apparatus(Elsevier Sci Ltd, 2019) Alcay, Salih; Ogutcu, Sermet; Kalayci, Ibrahim; Yigit, Cemal OzerBesides the classical geodetic methods, GPS (Global Positioning System) based positioning methods are widely used for monitoring crustal, structural, ground etc., deformations in recent years. Currently, two main GPS positioning methods are used: Relative and Precise Point Positioning (PPP) methods. It is crucial to know which amount of displacement can be detected with these two methods in order to inform their usability according to the types of deformation. Therefore, this study conducted to investigate horizontal and vertical displacement monitoring performance and capability of determining the direction of displacements of both methods using a developed displacement simulator apparatus. For this purpose, 20 simulated displacement tests were handled. Besides the 24 h data sets, 12 h, 8 h, 4 h and 2 h subsets were considered to examine the influence of short time spans. Each data sets were processed using GAMIT/GLOBK and GIPSY/OASIS scientific software for relative and PPP applications respectively and derived displacements were compared to the simulated (true) displacements. Then statistical significance test was applied. Results of the experiment show that using 24 h data sets, relative method can determine up to 6.0 mm horizontal displacement and 12.3 mm vertical displacement, while PPP method can detect 8.1 mm and 19.2 mm displacements in horizontal and vertical directions respectively. Minimum detected displacements are found to grow larger as time spans are shortened. (C) 2018 COSPAR. Published by Elsevier Ltd. All rights reserved.Öğe The effect of GLONASS on position accuracy in CORS-TR measurements at different baseline distances(Selcuk Univ Press, 2022) Yurdakul, Omer; Kalayci, IbrahimGLONASS system; It has become the second system operating on a global scale after the GPS system in the world, after completing the satellite constellation and using it at full capacity as of 8 December 2011. Due to the increasing need for high accuracy and precision real-time location information, CORS networks have become widespread in the world. In Turkey, it was established as CORS-TR and opened for use in December 2008. Comprehensive studies investigating the effects of Network-Based RTK techniques (VRS, FKP, and MAC) in the COR-STR network are very limited due to the fact that the GLONASS system has been used at full capacity recently. In this paper, it is aimed to determine the effect of measurements derived from the Network-Based RTK techniques in the CORS-TR network of the GLONASS system on the location accuracy, and thus to make a business plan according to the accuracy and precision requirements of all civil and military users. For this purpose, simultaneous measurements were made with 6 GNSS receiver devices of the same brand and model. A total of 308,908 epoch data (northing value, easting value, and ellipsoidal height: projection coordinates (ITRF96 Datum, 2005.00 Reference Epoch)) were collected at one-second intervals in each technique and for seven days of measurements. As a result of the evaluation and analysis of the data sets obtained with the measurements; It has been observed that the GLONASS system has a positive effect on position accuracy, but in some cases, it also has disruptive effects. It has been observed that the most important contribution is to increase the number of visible satellites and to enable measurements with GLONASS satellites in cases where GPS satellites alone are not sufficient, especially in areas where the satellite elevation angle is narrowed, such as city centers, and forest areas.Öğe Impact of Baseline Distance and Interstation Height Difference On the Accuracy of GPS-Derived Station Coordinates(Iop Publishing Ltd, 2016) Kalayci, Ibrahim; Yuksel, Bekir; Ogutcu, SermetThis paper investigates the accuracy comparison of scientific and commercial GPS processing software for varying length of baselines and interstation height differences. European Reference (EUREF) Permanent Network Stations were used for the processing. GAMIT/GLOBK research GPS processing software (version 10.6) and Leica Geo Office (version 8.4) commercial GPS processing software were chosen for the experiment. TUBO EUREF GPS station was taken as a known station whose three-dimensional (3D) published coordinates are precisely known and the other stations were taken as unknown points whose 3D coordinates are calculated after the processing. In this way, minimally constrained adjustment was performed for each unknown station within the EUREF network and their coordinates were calculated w.r.t. TUBO station with using each software. Only independent (non-trivial) baselines are processed between known station and unknown stations. Processing was conducted for 10 different days with 24 hours rinex data of the stations. When choosing the GPS stations, we consider the interstation height difference and baseline distance between the chosen GPS stations. Baseline distances varying from 131 km to 495 km. Interstation height differences varying from 4 m to 1620 m. After the processing, differences between the calculated 3D Cartesian coordinates of the stations whose coordinates were assumed unknown and the published true coordinates of these stations were transformed to topocentric coordinates (north, east, up) to observe the error component in 3D space. Results show that vertical accuracy obtained from commercial software is significantly low and not consistent comparing with the scientific software. There is no significant difference observed for horizontal accuracy between the software but the horizontal accuracy obtained from the scientific software is slightly better than the commercial one. There is no strong correlation found between the baseline distance and the accuracy for each software but this is not the issue for interstation height differences. Regarding the interstation height differences, it is observed that height difference between station pairs effect the accuracy in up component. As height difference between baseline points grow vertical, error becomes larger, especially for commercial software.Öğe Investigation of network-based RTK techniques: a case study in urban area(Springer Heidelberg, 2016) Ogutcu, Sermet; Kalayci, IbrahimNetwork-based real-time kinematic (NRTK) GNSS (Global Navigation Satellite System) positioning system is one of the most commonly used in many countries for various applications which require instant and highly accurate positioning all around the clock. The main principle of this system is to generate reliable error models that can mitigate dispersive (e.g., ionospheric delay) and non-dispersive (e.g., tropospheric delay and orbit biases) errors which are the main sources for the degradation of the positioning accuracy. There are several correction techniques that have been implemented and used in NRTK concept. The objective of this study is to evaluate accuracy, precision, time to first fix (TTFF), and performance of carrier phase ambiguity fixing while maintaining the same survey conditions for VRS, FKP, and MAC NRTK techniques. The Turkish TUSAGA-Aktif CORS network was used to obtain the three NRTK corrections. In terms of accuracy, our results show that all the techniques are practically the same and the horizontal positioning accuracy is in the order of few centimeters for all techniques. As far as precision and TTFF are concerned, VRS produced slightly better results comparing to the others. When it comes to ambiguity fixing performance in the dynamic environment, FKP produced the best results.Öğe Second-Order Ionospheres' Effect in Precise Point Positioning During the Solar Minimum and the Solar Maximum Periods in Turkey(Elsevier Science Bv, 2015) Ogutcu, Sermet; Kalayci, IbrahimThis paper investigates the second-order ionospheric effect on the estimated coordinates with using GIPSY 6.3 research software. Four IGS (International Global Service) stations were selected to perform precise point positioning (PPP) for the three different days. Three of these stations are in Turkey (ISTA, TUBI, ANKR) and the other one is in CYPRUS (NICO). The chosen days are within the solar maximum and the solar minimum periods which are the 294th day of year 2001 (DOY 294, 2001, solar maximum), 82th day of year 2014 (DOY 82, 2014, solar maximum) and the first day of year 2009 (DOY 1, 2009, solar minimum). Vertical Total Electron Content (TECV) was determined for the chosen IGS stations in these days. Approximately 5 TEC unit (TECU) changes for DOY 1, 2009 and 50-60 TECU changes for DOY 82, 2014 and DOY 294, 2001 were observed. 24 hours rinex observation files with 30 seconds sampling interval for each station and each day were processed with and without correcting the second-order ionosphere effect by GIPSY 6.3. The second-order effect is obtained from the difference between the two processes. The differences of XYZ Cartesian coordinates were transformed to topocentric coordinates (north, east, up) in order to analyze the second-order effect on the positioning more conveniently. The results show that the north component is affected significantly larger than the east and up components from the second-order ionospheric effect for each processed day. Maximum values of the north component between the two processes were observed in ANKR station (1.47mm) for DOY 294, 2001. East and up components are in the order of sub-millimeter level for each station and each day. The results of the difference between the two processes show that the impact of the second-order correction on positioning has a southward tendency for each station. This study, once again, clearly emphasized that the second-order ionospheric effect should be taken into account especially during the high solar activities period if high accuracy is needed. (C) 2015 The Authors. Published by Elsevier B.V.
